This is a bulky wool tam with some extra bulky wool/mohair blend in the middle and above the band.  The brown is naturally variegated Romney wool.  The gray is undyed Corriedale wool.  The grayer brown on the underside of the hat is Romney roving.  This looks grayer than it actually is.  The band is the same dark brown as the top of the hat.  The green stripes are Corriedale.